CST MWS Service Packs

Are the service packs for the CST products, incremental (requiring all to be installed) or differential (just the latest to be caught up) from the base installation?

CST service packs will contains updates and fixes for issues found in initial version. however, its not a must to install service packs. base installation should work well in terms of accuracy.

Yes, I realize that any service pack is 'differential', meaning all the code changes are included from the 'base install (SP0)'.
Thank you for your help!